Three immunological methods [radioimmunoassay (RIA), enzyme-linked immunosorbent assay, and radioimmunosorbent technique] were established for quantification of the potentially mutagenic O6-ethyldeoxyguanosine (O6-EtdGuo) in DNA treated with the carcinogen ethylnitrosourea in vivo or in vitro. To obtain high-affinity antibodies for specific detection of low levels of O6-EtdGuo in small amounts ...

An enzyme-linked immunosorbent assay (BA-ELISA) involving use of biotin-labeled anti-rabbit IgG and avidin-labeled horseradish peroxidase was developed for the measurement of O6-methyl-2'-deoxyguanosine (O6-MedGuo). Up to 5 micrograms of methylated DNA was enzymatically hydrolyzed, and the extent of inhibition of binding of immobilized O6-MedGuo-bovine serum albumin to rabbit anti-O6-MedGuo was...

An immunohistochemical procedure was developed which allows the localization of the DNA lesion O6-ethyldeoxyguanosine (O6-EtdGuo) within tissues and organs. The method permits the detection of 24,000 residues of O6-EtdGuo per diploid nucleus. We have used this procedure to localize N-ethyl-N-nitrosourea (ENU)-induced O6-EtdGuo in the rat brain. Shortly after a single injection of ENU, we observ...

O6-alkylguanine-DNA alkyltransferase (AGT) protects from the mutagenic and toxic lesions induced by 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), and in many tumors, AGT overexpression provides a means of resistance. To circumvent this, O6-benzylguanine, an inactivator of AGT, has been developed and is currently in clinical development with BCNU; however, the potential long-term toxicities assoc...

The stationary-phase sigma factor, RpoS, influences the expression of factors important in survival of Pseudomonas chlororaphis O6 in the rhizosphere. A partial proteomic profile of a rpoS mutant in P. chlororaphis O6 was conducted to identify proteins under RpoS regulation. Five of 14 differentially regulated proteins had unknown roles. Changes in levels of proteins in P. chlororaphis O6 rpoS ...

Site-dependent Eu3+ photoluminescence (PL) was examined utilizing the structural difference of two doped alkaline earth lanthanum tantalates with B-site-ordered double perovskite-type structure (AA’)[BB’]O6, viz. (CaLa1?xEux)[CaTa]O6 (CLTO:Eu3+) and (Ba2)[La1?xEuxTa]O6 (BLTO:Eu3+) (x = 0.01, 0.10). The locations ions were experimentally determined by X-ray absorption near edge Eu LIII confirmed...

OBJECTIVES To evaluate the toxic effects and maximum tolerated dose of topical carmustine [1,3-bis(2-chloroethyl)-1-nitrosourea] following intravenous O6-benzylguanine in the treatment of cutaneous T-cell lymphoma (CTCL), and to determine pharmacodynamics of O6-alkylguanine DNA alkyltransferase activity in treated CTCL lesions. DESIGN Open-label, dose-escalation, phase I trial. SETTING Derm...

Extended (histone H1-depleted), 11-nm-thick chromatin fibers and condensed 25- to 35-nm-thick chromatin fibers, representing the first and second level of DNA folding in chromatin, respectively, as well as nucleosome core particles, were isolated from fetal rat brain cells and briefly exposed to N-ethyl-N-nitrosourea (EtNU) in vitro. The O6-ethyl-2'-deoxyguanosine (O6-EtdGuo):2'-deoxyguanosine ...

Human cells that lack O6-alkylguanine DNA alkyltransferase (AT) activity can remove O6-butylguanine (O6-nBuG) produced in cellular DNA by exposure to N-n-butyl-N-nitrosourea as determined by radioimmunoassay of enzyme digests of DNA. Fibroblasts from xeroderma pigmentosum (XP) complementation groups A and G that show less than 5% unscheduled DNA synthesis following exposure to UVC failed to rem...

We have previously demonstrated (A. E. Pegg, Cancer Res., 50: 6119-6129, 1990) that O6-benzylguanine (O6-BG) enhances nitrosourea, temozolomide, and cyclophosphamide activity in malignant glioma xenografts growing in athymic nude mice. More recently, we have demonstrated (V. J. Patel et al., Clin. Cancer Res., 6: 4154-4157, 2000; P. Pourquier et al., Cancer Res., 61: 53-58, 2001) that the combi...